What is one of the possibly reason why cooling performance is impaired

What is one of the possibly reason why cooling performance is impaired?

Symptom

Poor cooling performance - what should I do?

Checkpoint

Once a unit has been installed with the required amount of refrigerant (Gas) and there are no respective system leaks. There is no need to neither add nor replace the refrigerant within the sealed Air conditioning system.

If the cooling performance is impaired then,

1.Select the cooling mode and set point temperature to lowest value via the remote control (18℃, is the lowest temperature value in cooling mode). Allow system to operate for approximately 15 minutes.

2. Whilst the outdoor system is operating on cooling and producing cooling air to the indoor unit. Inspect the exposed copper tubing, as per image below, generally if the correct volum of refrigerant (gas levels) is contained within the sealed system. There should be no signs of ice formation on the smaller of the two pipes and the larger pipe, should be cold and covered with condensation. Please contact the service center if the outdoor unit does not run or cold air does not blow from the indoor unit.